FPO: Your body is made up of 60-75% water and when you sweat, you begin to lose water quickly.
But sweat isn’t just water; it’s made up of electrolytes, especially sodium, which makes up about 90% of the electrolytes you lose in sweat. Sodium and potassium work together to help regulaate and maintain fluid balance, while magnesium and calcium are essential for muscle functional and energy metabolism.
If you’re just drinking water, you’re not replacing components your body needs to perform. It’s important to replace both the fluid and electrolytes, specifically the sodium lost in sweat, otherwise you’re going to risk feeling like crap (and no one wants that. Especially in the middle of workout). Electrolyte replacement is most important during high-intensity training lasting >1 hours.